Effect of aluminium doping amount on the electrochemical properties of ZnO nanoparticles as anode for lithium ion batteries

Aluminium (Al)-doped ZnO nanoparticles (NPs) have been synthesised by a simple solvothermal method at low temperature. The electrochemical properties of the obtained products as anode for lithium ion batteries were examined through galvanostatic discharge-charge, cyclic voltammetry and electrochemical impedance spectroscopy measurements. The results show that the reversible capacities of Al-doped ZnO NPs are higher than the capacities of pure ZnO synthesised under the same experimental conditions. ZnO NPs doped with 2% (molar ratio) of Al show the best electrochemical properties with reversible specific capacities of 418 mA·h·g^-1 at a current density of 50 mA·g^-1. The enhanced electrochemical performance of this material could be attributed to the improved electronic conductivity because of the doping of Al³⁺ at an appropriate concentration.